Experimental and numerical study of concrete at high strain rates in tension

Test results for concrete loaded at high strain rates in tension, obtained with a new experimental technique, and numerical simulations of those exper iments by discrete element method (DEM), are presented in this paper. The e xperimental method is based on the Hopkinson bar principle combined with th e spalling phenomenon. The setup was equipped with a high-speed CCD camera (10(6) pictures/s) for the recording of the fracture process. This original technique allowed for determination of the tensile strength of wet concret e at high strain rates (higher than 20 s(-1)). Such data are unique in the literature, particularly in this range of strain rates, and they demonstrat e a high rate sensitivity of tensile strength. A local cumulative criterion is proposed and implemented in the numerical analysis. The discrete elemen t method, adapted for cohesive materials. approximates the concrete as an a ssembly of rigid particles connected by interaction laws. The experimental data and the numerical results of the test simulations are presented and co mpared. (C) 2001 Elsevier Science Ltd. All rights reserved.